Sylvania



(No Model.)

- B. G. LAMM-E. SYSTEM OI ELEGTRIGAL DISTRIBUTION AND REGULATION. No. 606,015. Patented June 21,1898.

W/TNESSES lNVENTOFf UNrTnn STATns PATENT (Enrica,

BENJAMIN G. LAMME, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO THE \VESTINGIIOUSE ELECTRIC AND MANUFACTURING COMPANY, OF PENN- SYLVANIA.

SYSTEM OF ELECTRHCAL DlSTRlBUTlUN AND REGULATlON.

SPECIFICATION forming part of Letters Patent No. 606,015, dated June 21, 1898.

Application filed February 10, 189 8. Serial No1 669,846. (N model.)

T0 60% 1071/0777 it may concern: of the alternating current will remain practi- Be it known that l, BENJAMIN G. LAMME, a cally constant notwithstanding variations in citizen of the United States, residing in Pittsthe load, provided the field-charge and the apburg, in the county of Allegheny and State of plied direct-current electromotive force re 5 Pennsylvania, have invented a new and usemain constant; but if the alternating current 55 ful Improvement in Systems of Electrical Disis not in step with its electromotive force there tribution and Regulation, (Case No. 769,) of will be two components, one of which is in which the following is a specification. step with the electromotive force and is rep- My invention relates to the transformation resentedby the direct current supplied to the of direct currents to alternating currents, and transformer and the other of which is at right 60 has for its object to provide a method and a angles to the electromotive force and is not means whereby the speed of the rotary transrepresented by any corresponding direct ourformer employed maybe maintained substanrent. This right-angled component may be tially constant irrespective of changes in the either a leading or a lagging current and will I 5 amount of inductive load on the alternatingreact upon the field-magnet so as to magnetize 65 current circuit. or demagnetize it, as the case may be. If it It is well known that a rotary transformer exerts a magnetizing effect, it strengthens the employed in transforming alternating to difield-magnet,and the speed of the rotary transrect currents has a certain definite speed formerdecreases. If it demagnetizes the field which is determined by the rate of alternamagnet, the speed of the transformer will in- 7o tions of the current supplied to its alternatcrease. Therefore if the alternating-current ing-current terminals. The speed therefore circuit carries an inductive l0adsuch, for remains constant even though the electromoexample,asinduction-motorswhich changes tire force be varied, provided the rate of alterfrom time to time, the variationsin the amount nationsis not changed. This transformation of inductive load will cause variations in the 75 from alternating currents to direct currents is speed of' the transformer, which will in turn the one most usually practiced; but it somevary the speed of the motors driven by it. In times occurs that a demand is made for alterorder to obviate this Variation in speed with nating current for driving induction-motors changes in the amount of inductive load, I

or for other purposes where the only readilypropose to employ a small direct-current gen- 80 available source of current is a direct-current erator for exciting the field-magnet of the rogenerator or a plant embodying several such tary transformer, which may have either a generators. Under such conditions it beshunt, a series, or a eompoundwinding, but comes necessary, in order to utilize the existwhich must be normally operated to produce 3 5 ing plant, to transform some or all of the dian electromotive force which corresponds to 85 rect current to alternating current. It is of a degree of field-magnet excitation very much course desirable to employ a rotary transbelow saturation. This exciting-generator is former for this purpose; but with such redriven either by an alternating-current moversed operation of the rotary transformer tor, which is in turn driven by current sup- 40 the rate of alternations of the current obviplied by the rotary transformer, orit is belted ously depends upon the speed of the armadirectly to the rotary transformer. If the ture, and this in turn is dependent upon the amount of the alternating-current inductive field-magnet strength and the direct-current load on a rotary transformer changes so that electromotive force supplied to the armature. the rate of alternations decreases, for exam- If the rotary transformer is delivering an alple, then the exciting-generator and the mo 5 ternating current that is instep with its elector driving the same will also decrease in tromotive force, the armature reactions of the speed. This action will also decrease the exdirect current are opposed to and practically citing electromotive force of the rotary transneutralize those of the alternating current. former, and as the exciter is unsaturated a Under this condition the rate of alternations small drop in speed will produce a relatively large drop in the eleetromotive force. This lowering of the exciting eleetron'iotive force will thus weaken the ileld oi the rotary transformer and effect an increase of its armature speed up to near the normal. On the other hand, an increase in speed of the rotary transformer will be accompanied by an increase in the exciting electromotive force which will act immediately to lower the speed of the transformer.

I11 the accompanying drawings, Figure 1 is a diagram of a system embodying my invention, and Fig 2 is a similar diagram of a modification.

Referring particularly to Fig. 1, l is a direct-current generator which may have any suitable type of field-magnet winding, that shown being of the compound variety. 2 is a rotary transformer receiving direct current from a generator 1 and supplying alternating current to the mains '3, i, 5, and 6. 7 is a two-phase motor, which represents the inductive load upon the alternating-current circuit. The field-magnet winding 8 of the rotary transformer 2 is shown as excited by a directcurrent generator 9, having a series iicldmagnet winding 10, this probably being the.

most desirable winding for this system, although the invention is not limited in this re spect. The armature of the generator 0 is shown as belted to a small two-phase motor 11, which receives its driving-current from the mains at, 5, and (3. The operation of this system effects a substantially constant speed of the rotary transformer notwithstand' ing changes in the amount of inductive load on the alternating-current circuits supplied by it, as has been already set forth.

In Fig. 2 the main direct-current generator 1 is shown as a shunt-wound machine and the rotary transformer 2 as having a ficld magnet winding 8, excited by a (IiIGCikGlIII'GDt generator 0, having a series field-magnet winding 10, the same as in the form illustrated in Fig. 1. The alternating-current circuits 3, at, 5, and (3 are also shown as provided with an inductive load, represented by a two-phase motor 7. In this organization of apparatus, however, the exciting-generator 9 is belted directly to the rotary transformer instead of being driven by a separate motor, as in the other form. It has been found in practice that this method gives very attisi'aetory results, and that the variations in speed of the rotary transformer are less than onetenth as great as is the case when the transformeris operated as ashnnt-wouml machine.

I claim as my invention 1. A system of distribution comprising a direct-current generator,a rotary transformer receiving current therefrom and supplying alternating currents to translatin devices, a generator for exciting the iield-magnetoij' said rotary transformer and means (.lepemlent upon changes in the amount oi. inductive load on the alternatingcnrrent circuit or circuits for automatically varying the speed of the exciting-generator.

2. An electrical transformingand distribnting system, a source of. direct currents, a retary transformer receiving current from said source and supplying altermtting-current translating devices, a direct-current generator for exciting the iieldmagnet of said rotary transformer and means for automatio ally varying the speed of the exciting-generator as the amount of inductive load on the alternating-current circuit varies.

In an electrical transforming and distributing system, the combination with a source of direct eurren t, a rotary trans i'rn'mer, an exciting-generator for the iield-magnet of such transformer operated to produce an electromotive force corres ionding to a iicidmagnet excitation much below saturation and means for controlling the speed oi. said. exciter in accordance with clutnges in the amount of ind uctive load on the alternating current circuit or circuits supplied. by the rotary trai'isiornler.

t. The method of maintaining comatant speed in a rotary transformer for trai'miform ing direct to alternating currents, which consists in exciting its fieldanagnet by a direct current generator and varying the speed oi. such generator as the amount oi inductive load on the alternatiiigeurrent circuit varies.

In testimony whereof I have hereunto subscribed my name this Sth day oi. February, A. D. 1898.

liltbhi. G. I... MM l Witn esses:

Wnsnny G. Mann, ll. U. Tnxnu. 

